Electronic devices often have a number of physical keys which may be used for inputting instructions to such devices. In order to facilitate use of electronic devices in low lighting conditions, electronic devices sometimes backlight such physical keys. When backlighting keys, an effect known as light leak may sometimes occur. Light leak occurs when light is emitted from undesirable portions of the electronic device. This can result in unbalanced and unattractive backlighting of keys.
To avoid having to provide a light source beneath every key, the light from a light source (e.g. a light emitting diode) is guided to multiple keys. In some devices, a light guide foil is positioned underneath a set of keys and the light guide foil functions to spread out the light from the light source. In some cases, a side-fire LED or similar source is used to inject light into the foil. However, side-fire LEDs tend to be costly. Top-fire LEDs are thus sometimes used as a light source to inject light into the foil; however, this arrangement presents difficulties when designing to ensure a shallow depth to the key assembly.
Like reference numerals are used in the drawings to denote like elements and features.